In a type of muffler which is common in exhaust systems for marine engines, there is a container with a water trap, mounted upright, usually beside the engine. In order to make the noise muffling effective without increasing the counter pressure to an unacceptably high level, these containers must be made relatively large. An in-line engine with a power of 150-200 horsepower can require a container with a diameter of 200 mm and a height of over 500 mm in order to achieve a noise level which is sufficiently low to meet environmental standards. A 300 horsepower V-engine thus requires two such containers which, when mounted beside each row of cylinders, take up a great amount of space in the engine room. This reduces accessability for service and repairs. The problems are particularly great in power plants with twin V-engines. This type of muffler installation generally requires relatively long tubing with many bends.